/*
 * Copyright (C) The Apache Software Foundation. All rights reserved.
 *
 * This software is published under the terms of the Apache Software License
 * version 1.1, a copy of which has been included with this distribution in
 * the LICENSE.txt file.
 */
package org.apache.avalon.framework.logger;

/**
 * This is a facade for the different logging subsystems.
 * It offers a simplified interface that follows IOC patterns
 * and a simplified priority/level/severity abstraction. 
 *
 * @author <a href="mailto:peter@apache.org">Peter Donald</a>
 */
public interface Logger
{
    /**
     * Log a debug message.
     *
     * @param message the message
     */
    void debug( String message );

    /**
     * Log a debug message.
     *
     * @param message the message
     * @param throwable the throwable
     */
    void debug( String message, Throwable throwable );

    /**
     * Determine if messages of priority "debug" will be logged.
     *
     * @return true if "debug" messages will be logged
     */
    boolean isDebugEnabled();

    /**
     * Log a info message.
     *
     * @param message the message
     */
    void info( String message );

    /**
     * Log a info message.
     *
     * @param message the message
     * @param throwable the throwable
     */
    void info( String message, Throwable throwable );

    /**
     * Determine if messages of priority "info" will be logged.
     *
     * @return true if "info" messages will be logged
     */
    boolean isInfoEnabled();

    /**
     * Log a warn message.
     *
     * @param message the message
     */
    void warn( String message );

    /**
     * Log a warn message.
     *
     * @param message the message
     * @param throwable the throwable
     */
    void warn( String message, Throwable throwable );

    /**
     * Determine if messages of priority "warn" will be logged.
     *
     * @return true if "warn" messages will be logged
     */
    boolean isWarnEnabled();

    /**
     * Log a error message.
     *
     * @param message the message
     */
    void error( String message );

    /**
     * Log a error message.
     *
     * @param message the message
     * @param throwable the throwable
     */
    void error( String message, Throwable throwable );

    /**
     * Determine if messages of priority "error" will be logged.
     *
     * @return true if "error" messages will be logged
     */
    boolean isErrorEnabled();

    /**
     * Log a fatalError message.
     *
     * @param message the message
     */
    void fatalError( String message );

    /**
     * Log a fatalError message.
     *
     * @param message the message
     * @param throwable the throwable
     */
    void fatalError( String message, Throwable throwable );

    /**
     * Determine if messages of priority "fatalError" will be logged.
     *
     * @return true if "fatalError" messages will be logged
     */
    boolean isFatalErrorEnabled();

    /**
     * Create a new child logger.
     * The name of the child logger is [current-loggers-name].[passed-in-name]
     *
     * @param name the subname of this logger
     * @return the new logger
     * @exception IllegalArgumentException if name has an empty element name
     */
    Logger getChildLogger( String name );
}
